Blower or compressor of the multi-cell construction



Jn. 24, 1961 H. J. VENEDIGER BLOWER OR COMPRESSOR OF THE MULTI-CELL CONSTRUCTION Filed March 18, 1959 WV w Am $1) g s \I C n I A \k i M MN HM. .WHH. .H .H. .M. H N V i. go ww BLOWER OR COMPRESSOR OF THE MULTI-CELL CONSTRUCTION Herbert Josef Venediger, 1 Heinrich-I-I'eiue-Strasse, Furth, Bavaria, Germany Filed Mar. 18, 1959, Ser. No. 800,347

1 Claim. (Cl. 230-152) This invention relates to a blower or compressor of multi-cell construction in which a rotor is arranged to rotate on a working cylinder provided 'With inlet and outlet openings, such rotor being mounted eccentrically to the axis of the cylinder and being provided with plateshaped working slides or vanes in radial or approximately radial :grooves, which slides, on the rotation of the rotor, exert a thrust of magnitude double the value of the eccentricity. Such slides are supported by their two end portions on rings mounted rotatably in recesses of the working cylinder.

This application is a continuation-impart of my earlier application Serial No. 700,623, filed December '4, 1957.

Hitherto, a considerable defect in the type of rotary piston compressor of the type to which this and the said earlier application relate, has been the comparatively low mechanical efficiency. This is due mainly to the fact that in each rotation of the rotor, the said narrow plate-shaped Working slides, of a width B, height H and thickness d, have two rubber actions of their side surfaces in the grooves of the rotor, in fact to the value '2 .e.B. This procedure involves considerable frictional losses, particularly at high speeds of rotation, whereby it is difficult to lubricate the grooves of the rotor and the Working slides efficiently as the rotor and slides continually tend to throw the lubricating oil outwards against the Wall of the cylinder. By reason of inertia effects and because the pressure acting on the slides sets them obliquely in the grooves, as far as their running clearance permits, edge effects arise which cause additional frictional forces and further reduce the mechanical efficiency of the apparatus.

If the rotor has a large number of working slides, *and therefore many cells, then, with good delivery, comparatively high compression pressures are produced. Although in this case the expenditure of power for the compression of the medium (air, gas, etc.) is high and the frictional loss increases correspondingly with the many Working slides, a satisfactory degree of adiabatic efficiency can be ensured if the rotation speed or peripheral speed of the rotor is kept comparatively low.

If, on the other hand, the rotor is provided with only a few working slides, then the frictional loss is comparatively low, but because of the gap losses on the periphery on the working cylinder only small compression pressures can be produced. With such a blower however, requiring to be driven at highest rotational speed or greater peripheral speed of the rotor for the purpose of reducing the gap losses, the frictional power is in an unfavourable ratio to the relatively low expenditure of power necessary to produce the through-put, so that hitherto the degree of adiabatic efliciency has been more unfavourable than with. the high-compression multi-cell compressors.

The present invention, in recognition of this state of affairs, aims at the improvement of the mechanical eificiency of blowers and compressors of the .multi-cell constructional type. The novelty consists in the fact that atent the working slides are provided with guide formations moving with small play in corresponding guide ways of Patented Jan. 24, 1961 the rotor so as to prevent any tilting of the slides in their ggrooves, ;said guide formations being supported at their outer ends on bearing rings rotatably arranged in known manner in recesses in the working cylinder.

Preferably, the said guide formations are of piston shape, working in cylindrical guide ways in the rotor.

According to another feature of the invention, the dimensions of the guide formations, which are preferably hardened and ground, and of the bores in the rotor, taking into account also the width of the grooves and the thick- .ness of the slides are so adapted to one another that the slides do not contact the walls of the grooves. The guide formations will usually project outwardly beyond the working edge of the slide to provide a small gap between that edge and the wall of the cylinder.

The guideways for the said guide formations on the (slides may, according to a further feature of the invention, be locatedin cartridges of wear-resistant material which in their turn are inserted into and fixed in the rotor body, for example by screwing or pressing. The object of this last feature is to be able to combine with one another for the guide formations and the cartridges, materials with the best possible running properties, independently of the material of the rotor.

The invention may also include the feature that those parts of the said radial ribs or swellings which are supported against the bearing rings in the cylinder wall are provided with wear-resistant facings or inserts of natural or synthetic material of the highest possible hardness and resistance to wear.

. The invention is illustrated diagrammatically in the accompanying drawing of one embodiment. In the 1 drawing:

Fig. 1 is a vertical longitudinal section through a rotary piston blower having four working slides;

Fig. v2 is a cross section taken through the bearing ring part on line 2-2 of Fig. 1;

Fig. 3 is a perspective view of a part of one of the working slides;

Fig. 4 shows in perspective one of the vanes with attached ribs or swellings of piston form; and

Fig. 5 is a cross section on line 55 of Fig. 4.

Referring first to Figs. 1-3, 1 indicates the body of the working cylinder, 2 and 3 the end covers of the cylinder, '-4 the rotor, and 5 the rotor shaft on which the rotor is keyed (-see Fig. 2). 6 and 7 are the bearing rings freely mounted at the ends of the cylinder body 1, for rotation in recesses formed in the cylinder bore. The four working slides are indicated by 8, 9, 1t and 11. The axis of the rotor 4 is eccentrically displaced relatively to the bore of the cylinder 1 by the amount 2 (see Fig. 2). This rotor is rotatably mounted by its shaft 5 being journalled in the end covers 2, 3. During rotation, the slides 8-11 are urged outwardly by centrifugal force.

Each working slide 8, 9, 1t 11 is formed or provided at its ends with a cylindrical guide formation, at one end with the guide 12 and at the other end with the guide 13. These guides 12 and 13 move in radial bores 14, 15, 16 and 17 as will be seen from Fig. 2. However, deviating from the drawing, where the axis of each guide piston is at right angles to the rotor axis, the axes of the guide formations may be inclined to the rotor radius, that is they may be at tangents to a circle of substantially less diameter than the rotor. The tips of the guides 12 and 13 may slide over the inner face of the guide rings :6 and 7 respectively.

The body 1 of the cylinder will be parted at opposite sides of a diametral plane to provide inlet and outlet passages 1 1' similar to the arrangement shown in my co-pending application for Patent No. 518,267.

The diameter of the guide pistons 12, 13 is preferably a multiple of the thickness d of the working slide. The guide pistons 12, 13 which, in the example shown, are supported against the bearing rings 6, 7, project beyond the working edge of the slide by the amount s, whereby at the extreme dead-centre position of the slide a gap is provided between the working edge of the slide and the inner wall of the cylinder 1. As Fig. 3 shows, the head of the guide piston is formed roof-shaped.

The-bearing rings 6, 7 have two or more through bores 18, 19, 20 and 21 so that lubricant fed to the bearing rings at their outer periphery by a lubricating pump (not shown) can pass through the cross bores directly to the running surface of the guide pistons.

In order to be able to reduce as far as possible the friction of the guide formations in the bores receiving them, lubricating oil is supplied directly to the guide formations through lubrication bores provided in the bearing rings, the outer periphery of these rings being connected to a lubrication pump.

Each working slide may be provided with more than two guide formations, in which case only those arranged on the two ends of the slide will project beyond the working edge of the slide to provide the small gap between the inner wall of the working cylinder and the working edge of the slide.

If, as mentioned above, the working slide is provided with more than two guide formations, then for the working slide a material of particular light weight and thereby also of only small centrifugal forces at very high speed can be used, without a harmful bending of the working slides at high compression pressures, since the bending length of the slide is limited by the plurality of guide pistons.

At very high rotational speed and at great peripheral speed of the rotor where for the avoidance of very great centrifugal forces particularly light working slides are desirable, the invention permits of the use of materials, for example synthetic materials, for the working slides which up till now could not be used as they would have been destroyed after a short time of contact with the bearing rings. With the present invention, this is excluded as the contact of the working slides with the bearing rings is taken over by the guide pistons.

Referring now to Figs. 4 and 5, there is indicated at 101, the vane of overall length L, and height H, and with a thickness d. its outer edge 102 is bevelled at both sides. At its ends, the vane 101 has firmly connected to it the guide pistons 103, 103, see Fig. 5, where the actual connecting elements for example rivets, between the vane and the guide pistons are not shown.

Deviating from Fig. 4, the guide pistons 103 and 103' may be arranged at the very end of the vane 101 instead of in the places shown, and/or may be of rectangular instead of round cross section.

The guide pistons 103 and 103' are provided at their outer ends with inserts 104 and 104 of a natural or synthetic material of the highest possible hardness and resistance to wear. These inserts 104 and 104 are welded or cemented in the said recesses and the end faces 105 and 105 of the pistons are so shaped that they pro ject beyond the working edge 102 of the vane 101 to provide a gap s.

During the rotation of the rotor, in radial or almost radial grooves of which the vanes 101 work, the faces 105 and 105' of the guide pistons 103 and 103' are con stantly supported against the bearing rings arranged ro tatably in recesses of the working cylinder. Such rings can be seen in the drawings filed with the said co-pending application.

As the insert pieces 104 and 104' of the guide pistons 103 and 103' are subjected practically to no wear, the said gap s remains for an almost unlimited time, With the smallest possible frictional losses, so that the blower or compressor has both high mechanical efliciency, a constant output and long life.

All measures of the invention may with equal advantage be applied to multi-cell flow resistant machines which, instead of dealing with air or gas supply or compress another compressible medium. Without adversely affecting the idea of the invention, the measures of the invention may be applied with the same advantage also to the so-called mechanisms where the slides are not slidably mounted in the rotor but are in the working cylinder itself and are under spring force.

The invention reduces the frictional surfaces in rotary piston machines with plate-like slides to the smallest possible amount and, with hardened and ground slides, with a small amount of play in the bores of the rotor itself, or in cylindrical guide cartridges inserted in such bores, a satisfactory guiding of the working slides and a substantially higher mechanical degree of efiiciency is obtained than with the hitherto known machines.

In particular, With very rapid working rotary blowers which have to compress the air or gas only to a pressure of a few metres of water column, and in which theoretically therefore, the power required for the drawing in and compression and pushing out of the air or gas is only comparatively small, whilst the frictional power may be considerable so that the adiabatic total degree of efficiency is correspondingly low. As a rule with the hitherto known rotary piston blowers of this kind, the value 0.40 to 0.45 is not exceeded. The invention, because of the considerably higher mechanical degree of efficiency gives an adiabatic total degree of efiiciency of over 0.60 as tests have shown. In a similar manner, the adiabatic total degree of efiiciency of rotary piston compressors of the multi-cell type construction which produced high compression pressures is increased.

What I claim is:

A rotary blower comprising, a cylinder having a peripheral wall and end walls, the peripheral wall being formed with inlet and outlet openings at opposite sides and the end walls being provided with aligned hearings on an axis eccentric to the axis of said peripheral wall, an annular recess in the inner face of said peripheral wall near each end, a bearing ring floating in each such recess with its inner face co-planar with the inner face of the peripheral wall of said cylinder, a rotor mounted in said bearings and extending between the opposite end walls, a plurality of equally-spaced radial grooves in said rotor extending from end to end, each said radial groove running through a radial hole near each end, a vane slidably mounted in each said radial groove and having a transverse cylindrical formation near each end to fill the respective radial hole, said cylindrical formations having their outer extremities bearing on the inner face of that bearing ring which is at the same end of the cylinder, said vanes defining pumping chambers between them as the rotor moves them past said inlet and outlet openings with the outer face of the rotor osculating the inner face of the peripheral wall and with the outer extremities of said cylindrical formations on the vanes extending above the outer edges of the vanes.

References Cited in the file of this patent UNITED STATES PATENTS 330,001 Conver et al. Nov. 10, 1885 1,364,014 Wittig Dec. 28; 1920 1,408,649 Shore Mar. 7, 1922 1,807,392 Davis May 26, 1931 2,367,326 Beckrnan Jan. 16, 1945 2,414,187 Borsting Jan. 14, 1947 FOREIGN PATENTS 22,059 France Nov. 30, 1920 560,906 France July 23, 1923 

